Atsushi Komemushi

Percutaneous Vertebroplasty for Osteoporotic Compression Fractures: Long-Term Evaluation of the Technical and Clinical Outcomes

OBJECTIVE The purpose of this article is to evaluate the technical and clinical outcomes of 194 patients with 500 osteoporotic vertebral compression fractures (VCFs) consecutively treated by percutaneous vertebroplasty, to investigate the long-term efficacy of percutaneous vertebroplasty, and to determine the frequency of new VCFs after percutaneous vertebroplasty. MATERIALS AND METHODS One hundred ninety-four patients (168 women and 26 men; mean age, 73.3 years; range, 44-89 years) with 500 VCFs (T5-L5) were enrolled in this study. Evaluation at each follow-up time point (1 day, 1 month, 4 months, 1 year, and then once yearly) included pain response by using a pain visual analog scale (VAS) and frontal and lateral radiographs of the thoracic and lumbar vertebrae regardless of the symptoms. RESULTS The mean volume of cement injected was 3.3 mL (range, 0.5-12 mL) per level. Cement leakage was seen at 213 levels (42.6%). The mean follow-up time was 31 months (range, 1-97 months). The mean VAS score was 7.6 before percutaneous vertebroplasty and 3.1 at 1 day, 2.3 at 1 month, 1.7 at 4 months, 1.5 at 1 year, 1.2 at 2 years, 1.0 at 3 years, 1.1 at 4 years, 0.9 at 5 years, 0.9 at 6 years, and 1.0 at 7 years after percutaneous vertebroplasty. New VCFs were confirmed in 103 vertebrae in 65 patients (33.5%), affecting 65 adjacent vertebrae (63.1%) and 38 nonadjacent vertebrae (36.9%). CONCLUSION Percutaneous vertebroplasty was effective in relieving the pain associated with osteoporosis-induced VCFs, and the analgesic effect was long lasting when no new VCF occurred. However, radiologic follow-up observation showed that new VCFs occurred in approximately one-third of the patients.

Efficacy of carbon dioxide for diagnosis and intervention in patients with failing hemodialysis access

Background: Carbon dioxide (CO2) is the only proven safe intravascular contrast agent in renal failure and contrast allergy. The use of CO2 as a contrast agent for the evaluation of failing dialysis fistulas has the potential to preserve residual renal function by eliminating the use of contrast material or decreasing the amount used for fistulograms. Purpose: To evaluate the feasibility of fistulography using CO2 for diagnosis and intervention in patients with failing hemodialysis access. Material and Methods: Dialysis access failure occurred in 94 patients (54 men, 40 women; mean age, 65 years; range, 32–89 years) on 146 occasions. CO2 was used as the first-choice contrast agent for fistulography and PTA. Fistulography was performed with the injection of CO2 in the brachial artery using a power injector. Results: Interventional treatment was indicated in 141 accesses. In 115 of these 141 cases, intervention was performed using CO2 fistulography alone. When the access flow stopped or decreased very much due to an occlusion and severe stenosis, we could not visualize the access by CO2 fistulography, or could not perform CO2 fistulography. For those cases, iodinated contrast fistulography was performed. When the vascular rupture, dissection, or clot formation occurred during intervention, iodinated contrast fistulography was performed. In three patients with arteriovenous fistula, manual injection of CO2 into the brachial artery resulted in reflux of the gas into the thoracic aorta causing transient loss of consciousness. Conclusion: CO2 is a useful contrast agent in the diagnosis and intervention of failing hemodialysis access, eliminating or limiting the use of iodinated contrast material. Caution should be exercised to prevent CO2 reflux into the aorta when injecting the gas into the brachial artery.

Water-soluble Polyvinyl Alcohol Microspheres for Temporary Embolization: Development and in Vivo Characteristics in a Pig Kidney Model

PURPOSE To preliminarily examine whether solubility of water-soluble polyvinyl alcohol (PVA) microspheres in blood plasma changes in proportion to their degrees of saponification. The study also examined their feasibility as a temporary embolic agents in the pig renal artery. MATERIALS AND METHODS Three types of PVA microspheres with the degrees of saponification of 97 mol% (S97), 98 mol% (S98), and 99 mol% (S99) were prepared. Seven kidneys in seven miniature pigs were embolized and divided into three groups so there would be at least two kidneys for each type of PVA. One animal in each group was euthanized immediately after angiography at 3 hours after embolization and the other one at 7 days after. In addition, one animal embolized with S99 microspheres was euthanized at 21 days after embolization. RESULTS With S97 microspheres, the vascular network had recovered to the preembolic state by 3 hours after embolization. With S98 microspheres, blood flow in the third-order branch had been restored in the same period. With S99 microspheres, the second- and lower order branches remained occluded until 21 days. Histopathologic specimens harvested at 3 hours revealed only a trace of PVA for S97 microspheres. With S98 microspheres, the vascular lumen was still found to be filled with PVA gel. With S99 microspheres, swollen microspheres densely filled the vascular lumen even on day 21. CONCLUSIONS Dissolution process in vitro and the duration of arterial occlusion in vivo were possibly related to the degree of saponification of PVA. This result may support feasibility of PVA microspheres as a temporary embolic agent.

Pancreatitis after transcatheter embolization of a splenic aneurysm

A 52-year-old woman was treated for a splenic aneurysm that was found on abdominal computed tomography (CT) during a preoperative assessment for rectal cancer. The aneurysm was embolized using the “double coil-delivered microcatheter technique,” and 4 ml of a mixture of N-butyl 2-cyanoacrylate (NBCA) and iodized oil (Lipiodol) (NBCA/Lipiodol = 1.0: 2.5) were injected into the aneurysm. The patient complained of left upper quadrant abdominal pain immediately after the procedure. A blood test 2 days after the procedure showed an increased white blood cell count (13 100/μl), C-reactive protein (13.36 mg/dl), and pancreatic amylase (428 U/l). Abdominal CT scan showed a huge cystic lesion at the pancreatic tail, in the center of which was a highly enhanced area due to accumulated NBCA-Lipiodol. Postembolization pancreatitis was diagnosed, and treatment with fasting and a drip infusion of nafamostat mesilate was started. The patient’s abdominal pain became less severe within 3 days, and the pancreatic enzyme level had normalized 14 days after treatment. On CT, the cystic lesion at the pancreatic tail was smaller 20 days after the procedure, and it had disappeared completely 75 days after the procedure.

Analysis of factors influencing accuracy and complications in CT-guided lung biopsy

Abstract Introduction: This study aimed to analyze factors influencing accuracy and complications in patients who underwent computed tomography (CT)-guided lung biopsy at our medical center. Material and methods: This study included all 107 patients (72 men, 35 women; mean age, 69 years; range, 41–83 years) who underwent CT-guided lung biopsy between January 2006 and October 2009. CT fluoroscopy was used in 45.7% of cases. Final diagnosis, when surgical resection was performed, was histopathological diagnosis from the lung lesion specimen, and when resection was not performed, clinical diagnosis after ≥6 months of follow-up. The accuracy of lung biopsy was assessed by comparison of biopsy results and final diagnosis. The influence of factors on accuracy was statistically analyzed. Results: Accuracy of CT-guided lung biopsy was 89.4%. None of the factors, including lesion size, lesion depth from pleura, lesion location, patient position, final diagnosis, and use or non-use of CT fluoroscopy, had any significant influence on accuracy. The only complications were Grade 1 and 2 pneumothorax and Grade 1 pulmonary bleeding. The incidence of pneumothorax and bleeding was significantly increased with smaller lesion size and significantly increased with greater lesion depth. In patients with pulmonary emphysema, bleeding was significantly less (p = 0.022). When CT fluoroscopy was used, bleeding was significantly increased (p < 0.001). Conclusions: None of the factors had any significant influence on accuracy. The incidence of pneumothorax and bleeding was affected by lesion size and lesion depth. When CT fluoroscopy was used, bleeding was significantly increased.

Asymptomatic paradoxical and symptomatic pulmonary air embolism during central venous catheter insertion

A 65-year-old man developed respiratory distress during insertion of a central venous catheter (CVC). The presence of gas in the pulmonary trunk and ascending aorta was observed on computed tomography (CT) scans performed immediately after insertion, and paradoxical air embolism (PAE) was diagnosed. There were no symptoms of cerebral or coronary arterial embolism, and the patient was maintained in the same supine position as during CVC insertion. CT conducted after 200 min confirmed disappearance of the gas, and the resting position was discontinued. No subsequent symptoms of PAE occurred. In this patient with respiratory distress during CVC insertion, CT revealed PAE, and PAE was resolved and systemic arterial embolism did not occur by maintenance of the supine position and O2 administration. This case also highlights the potential risk for the occurrence of asymptomatic PAE related to CVC insertion.

Differences in Trocar Positioning within the Vertebral Body Using Two Different Positioning Methods: Effect on Trainee Performance

Purpose. To evaluate the educational effect of the Japanese Society of Interventional Radiology 7th Academic Summer Seminar from a technical perspective. Materials and Methods. Nineteen trainees participated in the seminar. The seminar consisted of vertebroplasty trainings using swine with the single-plane landmark method and with the ISOcenter Puncture (ISOP) method. All trainees were advised by an instructor as they operated the instruments and punctured the vertebra. For each trainee, the accuracy in the final position of the needle tip of the initial puncture in each swine training was evaluated. Results. Error in the final position of the needle tip of ≥5 mm from the target puncture site occurred in the lateral direction in 42% (8/19) of trainees with the landmark method and 5% (1/19) with the ISOP method. No error ≥5 mm occurred in the vertical or anteroposterior directions. In terms of puncture accuracy, error in the lateral direction was significantly lower with the ISOP method than with the landmark method (2.2 ± 1.5 mm versus 5.6 ± 3.2 mm). Conclusion. This seminar was effective training for trocar placement for beginners. The puncture was more accurate with the ISOP method than with the landmark method.

Percutaneous bypass creation between hollow organs by modified gun-sight approach.

Abstract This animal study investigated the feasibility of creating a bypass between two hollow organs, using a modified gun-sight approach with a pull-through string and pull-through tow wire. Ten procedures (femoral arteriovenous shunt, n = 4; portacaval shunt, n = 4; cholangiogastrostomy, n = 2) were performed in six adult swine. Snares were inserted into the two hollow organs through the sheath and deployed at the site of bypass creation. When snares overlapped on fluoroscopy, a needle was inserted to pass through both snares. The string was inserted through the needle, with only the needle then withdrawn. The snare furthest from the skin was closed to capture the string and was then withdrawn. The other snare was withdrawn without closing. The string thus served as a pull-through string penetrating both hollow organs. This string was then attached to a pull-through tow wire, withdrawn, and exchanged for the pull-through tow wire. By withdrawing the pull-through tow wire, the delivery sheath connected to the pull-through tow wire was towed through the site of the bypass, and the stent was placed. In all cases, bypass creation was achieved. Percutaneous bypass creation using a modified gun-sight approach with a pull-through string and pull-through tow wire is feasible between two hollow organs.

Does Vertebroplasty Affect Radiation Dose Distribution?: Comparison of Spatial Dose Distributions in a Cement-Injected Vertebra as Calculated by Treatment Planning System and Actual Spatial Dose Distribution

Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution.

Transcatheter embolization for visceral pseudoaneurysm with situs inversus totalis

Abstract We present a case of visceral pseudoaneurysm with situs inversus totalis, which was treated by transcatheter embolization. A 58-year-old man with chronic pancreatitis and situs inversus totalis was admitted to our hospital for epigastric pain. On celiac arteriography, a pseudoaneurysm was detected at the anterior superior pancreaticoduodenal artery (ASPD). We catheterized the ASPD with a microcatheter introduced coaxially through a 5Fr catheter, and we isolated the pseudoaneurysm with microcoils. The patients recovery was uneventful and he was discharged 17 days after the procedure. We describe this case because of the rarity of this anomaly, and it is important in that recognition may help avoid mishaps at interventions, particularly in the emergency setting.